The Hornets opened the scoring on 38 minutes when Harvey Sparks’ free-kick from the right sailed all the way into the net.
But the Chats hit back three minutes into the second half. Jamie Yila’s driven cross caused havoc in the Horsham box, leading to Kareem Isiaka scrambling home from six-yards.
The draw – Horsham’s first at home this season – leaves the Hornets third in the Isthmian Premier, four points adrift of leaders Dartford who won 3-2 at Hendon.
Horsham host fourth-placed Cray Valley Paper Mills this coming Saturday in a huge game in the race for promotion.
See some of John Lines’ pictures from the game on this page and the ones linked, and read Horsham manager Dominic Di Paola’s thoughts in the West Sussex County Times, out every Thursday.
9. Promotion-chasing Horsham FC held by Chatham Town - the match in pictures
Promotion-chasing Horsham FC were held to a 1-1 draw at home by visiting Chatham Town Photo: John Lines
10. Promotion-chasing Horsham FC held by Chatham Town - the match in pictures
Promotion-chasing Horsham FC were held to a 1-1 draw at home by visiting Chatham Town Photo: John Lines
11. Promotion-chasing Horsham FC held by Chatham Town - the match in pictures
Promotion-chasing Horsham FC were held to a 1-1 draw at home by visiting Chatham Town Photo: John Lines
12. Promotion-chasing Horsham FC held by Chatham Town - the match in pictures
Promotion-chasing Horsham FC were held to a 1-1 draw at home by visiting Chatham Town Photo: John Lines